1. Field of the Invention
The present invention generally relates to personal watercraft vehicles. In particular, the present invention relates to a novel multiplex communication system capable of exchanging information between components of a personal watercraft vehicle.
2. Description of Related Art and General Background
In an effort to improve reliability and increase operator comfort and safety, personal watercraft (PWCs) vehicles, much like their land and air counterparts, have recently included electronic systems to assist watercraft operations as well as to control and monitor key watercraft components. For example, PWCs may employ electronic mechanisms, such as, sensors, gauges, and controllers, to furnish trekking information, such as watercraft velocity, air and water temperature, travel distance, and directional/navigation data. PWCs may additionally employ such mechanisms to operational information, such as, indicate fuel, oil, and battery levels, engine speed, engine temperature, and engine status.
Generally, these electronic mechanisms are electrically coupled to specific PWC components, requiring dedicated communication paths or links therebetween. Such dedicated links are typically achieved by implementing a network of wired interconnections between the mechanisms and components. Naturally, the more features incorporated in PWCs, the more sophisticated the electronic systems, and the more complicated and cumbersome the wiring networks. In some cases, the wiring networks are configured as wiring harnesses, comprising bundled wires and cables, and conventional methods for configuring, installing, and maintaining wiring networks may prove to be difficult and cost-prohibitive.
Moreover, the drawbacks of conventional wiring networks are exacerbated by the fact that PWCs suffer from strict space limitations. By design, PWCs contain hydrodynamic profiles and contours that subject wiring harnesses to cramped spaces, odd angles, and complex routing configurations, which may require the bending, curving, and twisting of the harness and, hence, compromise the integrity of the harness""s bundled wires. Consider, for example, the cross-sectional side view of a PWC 100, as depicted in FIG. 1. PWC 100 includes an instrumentation panel or cluster 104, facing towards the operator as he or she is seated in a straddle-type seat 101, in order to display information to the operator. Such information may include display trekking and operational information, such as watercraft velocity, air and water temperature, battery levels, engine speed, engine temperature, and engine status. Cluster 104 is coupled to various electronic mechanisms via a conventional wiring harness 106. In particular, conventional wiring harness 106 comprises a plurality of wires connecting cluster 104 to the electronic mechanisms coupled to the PWC 100 components that furnish the desired information.
Cluster 104 may be mounted on a cluster mounting portion 108 on the bow portion 110 of the PWC 100 deck. The cluster mounting portion 108 may have a substantially slanted and streamlined profile from its aft end 108A to its fore end 108B. As illustrated in FIG. 1, such a profile limits the space available to route a large conventional wiring harnesses 106 that provides connectivity between cluster 104 and various PWC 100 components.
Furthermore, PWC 100 may include a bow storage compartment 112 used for storing items. Storage compartment 112 may be disposed in bow portion 110 of PWC 100, underneath mounting portion 108. In this configuration, mounting portion 108 may be hingedly-attached, via a hinge 109, to bow portion 110 and serve as a hood or lid to storage compartment 112. Mounting portion 108 may, therefore, be selectively opened or closed to provide entry into, or conceal, storage compartment 112. Such opening and closing of mounting portion 108 may, over time, compromise the integrity of the bundled wires within conventional wiring harness 106.
It will be appreciated that wiring networks are also susceptible to the harsh conditions typically experienced by PWCs 100. Wiring networks have to be protected from external influences, such as, moisture, rapid temperature fluctuations, salt, dirt, vibrations, and mechanical impacts. Given the strict space limitations noted above, it may be difficult to ensure the protection of conventional wiring networks from these external influences.
It will also be appreciated that conventional wiring networks limit the number of modifications and upgradeable options available on PWCs. Simple changes to cluster 104 displays, for example, may require identifying associated cables, untangling wiring harnesses, installing new cables, and test/troubleshooting new connections. The performance and expense of such tasks generally discourage PWC modifications.
Systems and methods consistent with the principles of the present invention, as embodied and broadly described herein, provide for a multiplex communication system capable of exchanging information between components of a personal watercraft vehicle.
In one embodiment, the multiplex communication system includes an engine electronic control unit electrically coupled to a plurality of watercraft engine sensors in which the watercraft engine sensors are operatively coupled to the watercraft engine and generate watercraft engine-related data and the engine electronic control unit is configured to process the engine-related data. The system also includes a multipurpose electronic control unit electrically coupled to a plurality of watercraft operation sensors in which the watercraft operation sensors are operatively coupled to a plurality of watercraft components and generate watercraft operational data and the multipurpose electronic control unit is configured to process the operational data. The system further includes a cluster electronic control unit coupled to a cluster display apparatus in which the cluster display apparatus is configured to display the engine-related and operational data. The system also provides for a system bus configured to operatively interconnect the engine electronic control unit, the multipurpose electronic control unit, and the cluster electronic control unit and arranged to support the transmission of said engine-related and operational data. Each of the electronic control units communicate with each other and exchange data via the system bus.
Additional aspects of the present invention include providing the electronic control units with processing mechanisms and associated memory devices, wherein the processing performed by the electronic control units include computation of performance parameters, control message generation, and multiplexing/de-multiplexing and transmission/reception operations in accordance with the Controller Area Network transmission protocol.
Other aspects of the present invention include configuring the system bus as a 2-wire circuit and incorporating a terminating connector at one end of the bus to terminate the 2-wire bus circuit and incorporating a terminating resistor within the engine electronic control unit disposed at the opposite end of the 2-wire bus circuit to terminate the circuit. In addition, the interconnection of the electronic control units is achieved by arranging the system bus in a T configuration, such that the multipurpose electronic control unit is implemented as a bridge connecting the engine electronic control unit at one end of the system bus and the terminating connector at the opposite end of the system bus. The cluster electronic control unit is connected to the multipurpose electronic control unit between the engine electronic control unit and the terminating connector.